Leak Survey Explained: 5 Proven Ways It Finds Hidden Leaks

A leak survey is a structured inspection of a property’s water system to find out whether water is escaping and, if so, where. Rather than chasing one symptom, the technician works through the system in stages: confirm the loss at the meter, isolate which line is responsible, then pinpoint the spot with acoustic listening, thermal imaging or pressure testing.

Last updated: September 2026

Leak survey vs. leak detection: what is the difference?

The terms overlap, and many companies use them interchangeably. Leak detection usually means pinpointing a leak you already suspect, such as a warm patch on the floor or a wet spot in the lawn. A leak survey is broader. It checks an entire property or system for water loss, typically when you know something is wrong, like a bill that keeps climbing or a meter that will not stop, but have no idea where the water is going. On one house the two visits look almost identical. On multi-unit and commercial properties the difference matters more, because the survey has to cover many lines and rule areas in or out.

What happens during a leak survey

1. Confirm the loss. With every fixture off, a meter that keeps moving means water is escaping somewhere on the property side of the line.
2. Split the system. The technician isolates sections, such as the supply to the house, irrigation and any pool or spa line, and pressure tests each one to see which section is losing pressure.
3. Narrow the location. Acoustic listening on accessible points, a ground microphone in the yard, and a correlator on longer runs close in on the leak.
4. Confirm with a second method. Thermal imaging, a moisture meter, dye testing in a pool, or a camera in a drain line verifies the finding before anyone acts on it.
5. Mark and document. The location is marked, photographed where useful, and written up.
6. Recommend next steps. You get the findings, what was ruled out, and what a repair would involve.

Method	Best for	Limitation
Meter isolation test	Confirming that water is being lost on the property side	Shows that a leak exists, not where it is
Sectional pressure test	Finding which line or zone is losing pressure	Narrows the area rather than pinpointing the spot
Acoustic listening	Pressurized leaks in buried, under-slab or in-wall pipes	Works best when the pipe is under pressure and background noise is low
Thermal imaging	Hot-water leaks under floors and moisture patterns in walls	Less useful on its own for cold-water lines
Moisture meter	Confirming damp materials behind drywall or under flooring	Shows where materials are wet, which is not always where the leak is
Camera inspection	Drain and sewer lines	Applies to drain and sewer lines, not pressurized supply pipes

When a leak survey makes sense

• Your water bill has climbed with no change in how you use water, and nothing is visibly leaking.
• The meter keeps moving after every fixture in the house is shut off.
• A pool is losing more water than evaporation explains, and the equipment looks dry.
• You are buying, selling or renovating and want the plumbing checked for hidden losses before money changes hands.
• A multi-unit building, HOA or commercial property has water use that does not match what the units report.
• You need documentation for an insurance claim or a repair contractor.

What a good leak survey report includes

• The date, the property and the areas tested.
• The methods used on each area.
• The confirmed leak location, with photos or markings.
• The areas that were tested and ruled out, which is as useful as the finding itself.
• Recommended next steps.

How to prepare for a survey

• Know where your main shutoff and water meter are, and keep the meter box clear.
• Make sure the technician can reach the pool equipment pad, cleanouts and any irrigation controller.
• Note when the symptoms started and gather your last few water bills.
• Keep a pool at its normal water level and reasonably clear, since testing depends on being able to see the result.

Surveys on commercial and multi-unit properties

Larger properties have longer distribution runs, more zones and sometimes shared lines that serve several units, so the survey takes more time to isolate each section. The report matters more too, because property managers and boards use it to decide where repair money goes. If that describes your property, see how we approach commercial leak detection.

Why finding the loss early matters

The EPA WaterSense program reports that the average household’s leaks waste nearly 10,000 gallons of water every year, and that about one in ten homes has leaks wasting 90 gallons or more per day. Most of that loss is hidden, in buried lines and under slabs, which is exactly where a survey looks.

What it costs

Price depends on how much of the property has to be covered, how accessible the lines are and how long it takes to isolate the loss. You should get a number before the visit starts. Our leak detection cost guide explains what moves the price.

Questions people ask about leak surveys

Before booking anything, try the water meter test. If the meter is moving, call +1 (728) 224-6444 and describe what you are seeing. If the loss looks like it is out in the yard, our underground leak detection page explains how buried lines are traced, and our water leak detection overview covers the rest. If you are comparing providers, our guide to how to choose a leak detection company lists the questions to ask, and if an insurance claim is involved, see whether homeowners insurance covers leak detection.